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1 | /* common code for Memory.c and cd/Memory.c */ |
2 | |
3 | static int PadRead(int i) |
4 | { |
5 | int pad=0,value=0,TH; |
6 | pad=~PicoPad[i]; // Get inverse of pad MXYZ SACB RLDU |
7 | TH=Pico.ioports[i+1]&0x40; |
8 | |
9 | if(PicoOpt & 0x20) { // 6 button gamepad enabled |
10 | int phase = Pico.m.padTHPhase[i]; |
11 | |
12 | if(phase == 2 && !TH) { |
13 | value=(pad&0xc0)>>2; // ?0SA 0000 |
14 | goto end; |
15 | } else if(phase == 3 && TH) { |
16 | value=(pad&0x30)|((pad>>8)&0xf); // ?1CB MXYZ |
17 | goto end; |
18 | } else if(phase == 3 && !TH) { |
19 | value=((pad&0xc0)>>2)|0x0f; // ?0SA 1111 |
20 | goto end; |
21 | } |
22 | } |
23 | |
24 | if(TH) value=(pad&0x3f); // ?1CB RLDU |
25 | else value=((pad&0xc0)>>2)|(pad&3); // ?0SA 00DU |
26 | |
27 | end: |
28 | |
29 | // orr the bits, which are set as output |
30 | value |= Pico.ioports[i+1]&Pico.ioports[i+4]; |
31 | |
32 | return value; // will mirror later |
33 | } |
34 | |
35 | |
36 | #ifndef _ASM_MEMORY_C |
37 | static |
38 | #endif |
39 | u8 z80Read8(u32 a) |
40 | { |
41 | if(Pico.m.z80Run&1) return 0; |
42 | |
43 | a&=0x1fff; |
44 | |
45 | if(!(PicoOpt&4)) { |
46 | // Z80 disabled, do some faking |
47 | static u8 zerosent = 0; |
48 | if(a == Pico.m.z80_lastaddr) { // probably polling something |
49 | u8 d = Pico.m.z80_fakeval; |
50 | if((d & 0xf) == 0xf && !zerosent) { |
51 | d = 0; zerosent = 1; |
52 | } else { |
53 | Pico.m.z80_fakeval++; |
54 | zerosent = 0; |
55 | } |
56 | return d; |
57 | } else { |
58 | Pico.m.z80_fakeval = 0; |
59 | } |
60 | } |
61 | |
62 | Pico.m.z80_lastaddr = (u16) a; |
63 | return Pico.zram[a]; |
64 | } |
65 | |
66 | |
67 | #ifndef _ASM_MEMORY_C |
68 | static |
69 | #endif |
70 | u32 OtherRead16(u32 a, int realsize) |
71 | { |
72 | u32 d=0; |
73 | |
74 | if ((a&0xff0000)==0xa00000) { |
75 | if ((a&0x4000)==0x0000) { d=z80Read8(a); d|=d<<8; goto end; } // Z80 ram (not byteswaped) |
76 | if ((a&0x6000)==0x4000) { // 0x4000-0x5fff, Fudge if disabled |
77 | if(PicoOpt&1) d=YM2612Read(); |
78 | else d=Pico.m.rotate++&3; |
79 | dprintf("read ym2612: %04x", d); |
80 | goto end; |
81 | } |
82 | d=0xffff; |
83 | goto end; |
84 | } |
85 | |
86 | if ((a&0xffffe0)==0xa10000) { // I/O ports |
87 | a=(a>>1)&0xf; |
88 | switch(a) { |
89 | case 0: d=Pico.m.hardware; break; // Hardware value (Version register) |
90 | case 1: d=PadRead(0); d|=Pico.ioports[1]&0x80; break; |
91 | case 2: d=PadRead(1); d|=Pico.ioports[2]&0x80; break; |
92 | default: d=Pico.ioports[a]; break; // IO ports can be used as RAM |
93 | } |
94 | d|=d<<8; |
95 | goto end; |
96 | } |
97 | |
98 | // |=0x80 for Shadow of the Beast & Super Offroad; rotate fakes next fetched instruction for Time Killers |
99 | if (a==0xa11100) { // z80 busreq |
100 | d=Pico.m.z80Run&1; |
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101 | if (!d) { |
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102 | // needed by buggy Terminator (Sega CD) |
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103 | extern int z80stopCycle; |
104 | int stop_before = SekCyclesDone() - z80stopCycle; |
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105 | dprintf("stop before: %i", stop_before); |
106 | if (stop_before > 0 && stop_before <= 32) // Gens uses 16 here |
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107 | d = 1; // bus not yet available |
108 | } |
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109 | d=(d<<8)|0x8000|Pico.m.rotate++; |
110 | dprintf("get_zrun: %04x [%i|%i] @%06x", d, Pico.m.scanline, SekCyclesDone(), SekPc); |
111 | goto end; |
112 | } |
113 | |
114 | #ifndef _ASM_MEMORY_C |
115 | if ((a&0xe700e0)==0xc00000) { d=PicoVideoRead(a); goto end; } |
116 | #endif |
117 | |
118 | d = OtherRead16End(a, realsize); |
119 | |
120 | end: |
121 | return d; |
122 | } |
123 | |
124 | |
125 | //extern UINT32 mz80GetRegisterValue(void *, UINT32); |
126 | |
127 | static void OtherWrite8(u32 a,u32 d,int realsize) |
128 | { |
129 | if ((a&0xe700f9)==0xc00011||(a&0xff7ff9)==0xa07f11) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound |
130 | if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)d; return; } // Z80 ram |
131 | if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=YM2612Write(a&3, d); return; } // FM Sound |
132 | if ((a&0xffffe0)==0xa10000) { // I/O ports |
133 | a=(a>>1)&0xf; |
134 | // 6 button gamepad: if TH went from 0 to 1, gamepad changes state |
135 | if(PicoOpt&0x20) { |
136 | if(a==1) { |
137 | Pico.m.padDelay[0] = 0; |
138 | if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++; |
139 | } |
140 | else if(a==2) { |
141 | Pico.m.padDelay[1] = 0; |
142 | if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++; |
143 | } |
144 | } |
145 | Pico.ioports[a]=(u8)d; // IO ports can be used as RAM |
146 | return; |
147 | } |
148 | if (a==0xa11100) { |
149 | extern int z80startCycle, z80stopCycle; |
150 | //int lineCycles=(488-SekCyclesLeft)&0x1ff; |
151 | d&=1; d^=1; |
152 | if(!d) { |
153 | // this is for a nasty situation where Z80 was enabled and disabled in the same 68k timeslice (Golden Axe III) |
154 | if (Pico.m.z80Run) { |
155 | int lineCycles=(488-SekCyclesLeft)&0x1ff; |
156 | z80stopCycle = SekCyclesDone(); |
157 | lineCycles=(lineCycles>>1)-(lineCycles>>5); |
158 | z80_run(lineCycles); |
159 | } |
160 | } else { |
161 | z80startCycle = SekCyclesDone(); |
162 | //if(Pico.m.scanline != -1) |
163 | } |
164 | dprintf("set_zrun: %02x [%i|%i] @%06x", d, Pico.m.scanline, SekCyclesDone(), /*mz80GetRegisterValue(NULL, 0),*/ SekPc); |
165 | Pico.m.z80Run=(u8)d; return; |
166 | } |
167 | if (a==0xa11200) { |
168 | dprintf("write z80Reset: %02x", d); |
169 | if(!(d&1)) z80_reset(); |
170 | return; |
171 | } |
172 | |
173 | if ((a&0xff7f00)==0xa06000) // Z80 BANK register |
174 | { |
175 | Pico.m.z80_bank68k>>=1; |
176 | Pico.m.z80_bank68k|=(d&1)<<8; |
177 | Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one |
178 | return; |
179 | } |
180 | |
181 | if ((a&0xe700e0)==0xc00000) { |
182 | PicoVideoWrite(a,(u16)(d|(d<<8))); // Byte access gets mirrored |
183 | return; |
184 | } |
185 | |
186 | OtherWrite8End(a, d, realsize); |
187 | } |
188 | |
189 | |
190 | static void OtherWrite16(u32 a,u32 d) |
191 | { |
192 | if ((a&0xe700e0)==0xc00000) { PicoVideoWrite(a,(u16)d); return; } |
193 | if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)(d>>8); return; } // Z80 ram (MSB only) |
194 | |
195 | if ((a&0xffffe0)==0xa10000) { // I/O ports |
196 | a=(a>>1)&0xf; |
197 | // 6 button gamepad: if TH went from 0 to 1, gamepad changes state |
198 | if(PicoOpt&0x20) { |
199 | if(a==1) { |
200 | Pico.m.padDelay[0] = 0; |
201 | if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++; |
202 | } |
203 | else if(a==2) { |
204 | Pico.m.padDelay[1] = 0; |
205 | if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++; |
206 | } |
207 | } |
208 | Pico.ioports[a]=(u8)d; // IO ports can be used as RAM |
209 | return; |
210 | } |
211 | if (a==0xa11100) { OtherWrite8(a, d>>8, 16); return; } |
212 | if (a==0xa11200) { dprintf("write z80reset: %04x", d); if(!(d&0x100)) z80_reset(); return; } |
213 | |
214 | OtherWrite8(a, d>>8, 16); |
215 | OtherWrite8(a+1,d&0xff, 16); |
216 | } |
217 | |
218 | |